KABUL: Islamic State group has suffered a major setback after three of its standard bearers in Afghanistan were killed in drone strikes in less than one week. The top Islamic State commander in Afghanistan got killed by a U.S. air strike in the country's east. Hafez Saeed was the leader of Islamic State in the "so-called Khorasan state".

He was killed along with 30 other militants as they gathered in Achin district of Nangarhar province late on Friday.

Saeed was among a small but increasing number of senior Taliban militants who have switched allegiance to Islamic State, the radical Islamist movement that has seized territory in Iraq and Syria and inspired attacks worldwide.

The new IS loyalists have been targets for U.S drone strikes in Afghanistan, including top commanders Shahidullah Shahid and Gul Zaman.

The U.S. military has expressed concern about the budding Islamic State presence in Afghanistan - still struggling to quell the Taliban's insurgency - and is using its remaining military force in the country to prevent IS from turning into the powerful force that emerged after the American withdrawal from Iraq.